radeon: avoid double free in ci_dpm_init()

Several calls to ci_dpm_fini() will attempt to free resources that
either have been freed before or haven't been allocated yet. This
may lead to undefined or dangerous behaviour.

For instance, if r600_parse_extended_power_table() fails, it might
call r600_free_extended_power_table() as will ci_dpm_fini() later
during error handling.

Fix this by only freeing pointers to objects previously allocated.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: cc8dbbb4f62a ("drm/radeon: add dpm support for CI dGPUs (v2)")
Co-developed-by: Natalia Petrova <n.petrova@fintech.ru>
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/ci_dpm.c b/drivers/gpu/drm/radeon/ci_dpm.c
index 8ef25ab..b8f4dac 100644 (file)
--- a/drivers/gpu/drm/radeon/ci_dpm.c
+++ b/drivers/gpu/drm/radeon/ci_dpm.c
@@ -5517,6 +5517,7 @@ static int ci_parse_power_table(struct radeon_device *rdev)
        u8 frev, crev;
        u8 *power_state_offset;
        struct ci_ps *ps;
+       int ret;
 
        if (!atom_parse_data_header(mode_info->atom_context, index, NULL,
                                   &frev, &crev, &data_offset))
@@ -5546,11 +5547,15 @@ static int ci_parse_power_table(struct radeon_device *rdev)
                non_clock_array_index = power_state->v2.nonClockInfoIndex;
                non_clock_info = (struct _ATOM_PPLIB_NONCLOCK_INFO *)
                        &non_clock_info_array->nonClockInfo[non_clock_array_index];
-               if (!rdev->pm.power_state[i].clock_info)
-                       return -EINVAL;
+               if (!rdev->pm.power_state[i].clock_info) {
+                       ret = -EINVAL;
+                       goto err_free_ps;
+               }
                ps = kzalloc(sizeof(struct ci_ps), GFP_KERNEL);
-               if (ps == NULL)
-                       return -ENOMEM;
+               if (ps == NULL) {
+                       ret = -ENOMEM;
+                       goto err_free_ps;
+               }
                rdev->pm.dpm.ps[i].ps_priv = ps;
                ci_parse_pplib_non_clock_info(rdev, &rdev->pm.dpm.ps[i],
                                              non_clock_info,
@@ -5590,6 +5595,12 @@ static int ci_parse_power_table(struct radeon_device *rdev)
        }
 
        return 0;
+
+err_free_ps:
+       for (i = 0; i < rdev->pm.dpm.num_ps; i++)
+               kfree(rdev->pm.dpm.ps[i].ps_priv);
+       kfree(rdev->pm.dpm.ps);
+       return ret;
 }
 
 static int ci_get_vbios_boot_values(struct radeon_device *rdev,
@@ -5678,25 +5689,26 @@ int ci_dpm_init(struct radeon_device *rdev)
 
        ret = ci_get_vbios_boot_values(rdev, &pi->vbios_boot_state);
        if (ret) {
-               ci_dpm_fini(rdev);
+               kfree(rdev->pm.dpm.priv);
                return ret;
        }
 
        ret = r600_get_platform_caps(rdev);
        if (ret) {
-               ci_dpm_fini(rdev);
+               kfree(rdev->pm.dpm.priv);
                return ret;
        }
 
        ret = r600_parse_extended_power_table(rdev);
        if (ret) {
-               ci_dpm_fini(rdev);
+               kfree(rdev->pm.dpm.priv);
                return ret;
        }
 
        ret = ci_parse_power_table(rdev);
        if (ret) {
-               ci_dpm_fini(rdev);
+               kfree(rdev->pm.dpm.priv);
+               r600_free_extended_power_table(rdev);
                return ret;
        }